[Silverlight入门系列]实现局部元素全屏(Element部分全屏)

来源：互联网发布：windows live注册页面编辑：程序博客网时间：2024/04/25 22:27

本文不讨论Silverlight全屏模式的实现，有关实现这个，可以参考TerryLee的这篇文章，核心代码就是这行：

Application.Current.Host.Content.IsFullScreen = !Application.Current.Host.Content.IsFullScreen;

本文要讨论的是Silverlight的局部元素全屏，即Element部分全屏。我们在做Silverlight项目中有时候客户有这种需求：希望放大界面的局部，比如一个列表面板啥的，而不是整个界面全屏。如下图：

实现部分全屏

实现起来也是比较简单，主要思路是用Popup实现弹出全屏，把需要全屏的元素放到容器里并设置为屏幕大小，然后整体实现全屏；当用户退出全屏的时候需要把元素恢复回原位置。好，我们写一个ElementsFullScreenProvider类，实现一个UIElement的扩展方法即可。

主要实现类：ElementsFullScreenProvider

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#region "Using Namespace"

using System;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Controls.Primitives;

#endregion

namespace ElementFullScreen

{

/// <summary>

/// Make partial UI elements full screen

/// Provider features:

/// make UI element full screen

/// exit full screen and restore UI element

/// support UIElement.ToggleElementFullScreen -- extension methods

/// </summary>

publicstatic class ElementsFullScreenProvider

{

#region Members

staticreadonly Popup PopupContainer;

staticreadonly Panel PopupContentContainer;

staticElementController _lastElementController;

#endregion

#region ElementController

classElementController

{

double_height = double.NaN;

double_width = double.NaN;

int_lastPanelPosition;

bool_lastPopupIsOpen;

readonlyDependencyObject _parent;

Thickness? _margin;

publicUIElement Element { get;private set; }

publicElementController(UIElement element)

{

Element = element;

varelem = element as FrameworkElement;

if(elem != null && elem.Parent != null)

{

_parent = elem.Parent;

}

publicvoid BringElementToFullScreen()

{

TryAction<frameworkelement>(Element, f =>

{

_height = f.Height;

_width = f.Width;

f.Height =double.NaN;

f.Width =double.NaN;

});

TryAction<control>(Element, f =>

{

_margin = f.Margin;

f.Margin =new Thickness(0);

});

if(_parent != null)

{

if

(!TryAction<panel>(_parent, p => { _lastPanelPosition = p.Children.IndexOf(Element); p.Children.RemoveAt(_lastPanelPosition); }))

if(!TryAction<contentcontrol>(_parent, c => c.Content = null))

if(!TryAction<usercontrol>(_parent, u => u.Content = null))

TryAction<popup>(_parent, p => { _lastPopupIsOpen = p.IsOpen; p.Child =null; });

}

publicvoid ReturnElementFromFullScreen()

{

TryAction<frameworkelement>(Element, f =>

{

f.Height = _height;

f.Width = _width;

});

TryAction<control>(Element, f =>

{

if(_margin.HasValue)

{

f.Margin = _margin.Value;

}

});

if(_parent != null)

{

if(!TryAction<panel>(_parent, p => p.Children.Insert(_lastPanelPosition, Element)))

if(!TryAction<contentcontrol>(_parent, c => c.Content = Element))

if(!TryAction<usercontrol>(_parent, u => u.Content = Element))

TryAction<popup>(_parent, p => { p.Child = Element; p.IsOpen = _lastPopupIsOpen; });

}

staticbool TryAction<t>(objecto, Action<t> action)

whereT : class

{

T val = oas T;

if(val != null)

{

action(val);

returntrue;

}

returnfalse;

}

#endregion

#region FullscreenElementID Attached Property

staticreadonly DependencyProperty FullscreenElementIDProperty = DependencyProperty.RegisterAttached(

"FullscreenElementID",typeof(Guid?), typeof(ElementsFullScreenProvider),new PropertyMetadata(null));

staticvoid SetFullscreenElementID(DependencyObject obj, Guid? value)

{

obj.SetValue(FullscreenElementIDProperty, value);

}

staticGuid? GetFullscreenElementID(DependencyObject obj)

{

return(Guid?)obj.GetValue(FullscreenElementIDProperty);

}

#endregion

#region Initialization

/// <summary>

/// Initializes the <see cref="ElementsFullScreenProvider"> class.

/// </see></summary>

staticElementsFullScreenProvider()

{

PopupContentContainer =new Grid();

PopupContainer =new Popup

{

Child = PopupContentContainer

};

Application.Current.Host.Content.FullScreenChanged +=delegate

{

if(_lastElementController == null)return;

if(!Application.Current.Host.Content.IsFullScreen)

{

ReturnElementFromFullScreen();

}

else

{

UpdateContentSize();

}

};

}

#endregion

#region Public Methods

publicstatic void BringElementToFullScreen(this UIElement element)

{

if(_lastElementController == null)

{

_lastElementController =new ElementController(element);

_lastElementController.BringElementToFullScreen();

PopupContentContainer.Children.Add(element);

PopupContainer.IsOpen =true;

}

publicstatic void ReturnElementFromFullScreen(this UIElement element)

{

ReturnElementFromFullScreen();

}

publicstatic void ReturnElementFromFullScreen()

{

if(_lastElementController != null)

{

PopupContentContainer.Children.Clear();

_lastElementController.ReturnElementFromFullScreen();

PopupContainer.IsOpen =false;

_lastElementController =null;

}

publicstatic void ToggleElementFullScreen(this UIElement element)

{

boolnewValue = !Application.Current.Host.Content.IsFullScreen;

booltoggle = false;

if(newValue)

{

if(_lastElementController == null)

{

element.BringElementToFullScreen();

toggle =true;

}

else

{

if(_lastElementController != null&& ReferenceEquals(element, _lastElementController.Element))

{

element.ReturnElementFromFullScreen();

toggle =true;

}

if(toggle)

{

ToggleFullScreen();

}

publicstatic void ToggleFullScreen()

{

Application.Current.Host.Content.IsFullScreen = !Application.Current.Host.Content.IsFullScreen;

}

#endregion

#region Private Method

privatestatic void UpdateContentSize()

{

if(Application.Current != null&& Application.Current.Host != null&& Application.Current.Host.Content != null)

{

doubleheight = Application.Current.Host.Content.ActualHeight;

doublewidth = Application.Current.Host.Content.ActualWidth;

//if (Application.Current.Host.Settings.EnableAutoZoom)

//{

// double zoomFactor = Application.Current.Host.Content.ZoomFactor;

// if (zoomFactor != 0.0)

// {

// height /= zoomFactor;

// width /= zoomFactor;

// }

//}

PopupContentContainer.Height = height;

PopupContentContainer.Width = width;

}

#endregion

}

</t></t></popup></usercontrol></contentcontrol></panel></control></frameworkelement></popup></usercontrol></contentcontrol></panel></control></frameworkelement>

调用的时候使用UIElement的扩展方法实现全屏：

 1: private void button1_Click(object sender, RoutedEventArgs e)

 2: {

 3:  SilverArea/*你希望全屏的元素*/.ToggleElementFullScreen();//调用UIElement的扩展方法

 4:  }

源码下载

本文源码下载请点击此处。主要就一个类ElementsFullScreenProvider.cs，用起来就一个函数ToggleElementFullScreen()，简单之极。

分类: SilverLight

标签: Silverlight

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